6-Benzylaminopurine(6-benzyladenine) and derivatives thereof have so far been known as an external preparation having the purposes of an antiaging effect for a skin and activation of cells by applying externally onto a scalp (refer to, for example, patent document 1). Further, it is known that an excellent hair growth effect is obtained by using 6-benzylaminopurine and derivatives thereof and fatty acids having a chain length of an odd number of carbon atoms and derivatives thereof in combination (refer to, for example, patent document 2).
Further, it is known as well that nonionic surfactants having an HLB value of 10 or less are effective for dissolving fatty acids having a chain length of an odd number of carbon atoms and derivatives thereof (refer to, for example, patent document 3).
On the other hand, it is known as well that polyhydric alcohols are effective as a solubilizing agent for 6-benzylaminopurine (refer to, for example, patent document 4).
However, it is difficult to stabilize dissolution of a preparation in which 6-benzylaminopurine and derivatives thereof are coexistent with fatty acids having a chain length of an odd number of carbon atoms and derivatives thereof, and in particular, the problem that active ingredients in the preparation are deposited at low temperature is involved therein. Accordingly, the stability at low temperature is not yet satisfactory in terms of actual use, and the existing situation is that hair growth promotor compositions having further excellent dissolution stability are still desired.    Patent document 1: Japanese Patent Application Laid-Open No. 320028/1993 (claims, examples and other)    Patent document 2: Japanese Patent Application Laid-Open No. 233037/1995 (claims, examples and other)    Patent document 3: Japanese Patent publication No. 37886/1990 (claims, examples and other)    Patent document 4: Japanese Patent Application Laid-Open No. 72321/1998 (claims, examples and other)